两种聚酯微球的体外降解机制研究
Study on the Degradation of Poly (d,l-lactide-co-glycolide) and Poly(Lactic Acid) Microspheres in vitro
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摘要: 目的:研究聚乳酸-羟基乙酸及聚乳酸微球降解的过程及机制.方法:用5种方法分别研究:①扫描电子显微镜观察微球外观形态及表面状态;②测定干燥失重;③凝胶渗透色谱法测定聚合物的平均相对分子量;④测定介质pH值;⑤测定介质中乳酸含量.结果:聚乳酸-羟基乙酸微球的降解呈现明显外形改变和蚀解,聚乳酸微球降解表现为明显的溶胀和伴有孔洞形成.两者均降解成为分子量分布小的低聚物,介质中乳酸量明显增加以及pH显著下降.共聚物微球的降解速度随羟基乙酸比例的增加而加快.结论:聚乳酸-羟基乙酸微球的降解为表面溶蚀与本体蚀解结合机制,而聚乳酸微球的降解为本体蚀解机制.Abstract: AIM:To study the in vitro deg radation and it's mechanism of poly-d,l-lactide-co-glycolide (PLGA) and poly-d,l-lactic acid (PLA) microspheres METHOD:Using fi ve approaches:(1)assessment of surface morphology of microspheres by scannin g electro n microsco